Binders having threaded posts for extending the thickness of a book such as a ledger are old and well known. Heretofore, the extra threaded posts for extending the thickness of the ledger have been supplied separately in an envelope. When a threaded post is needed, the whereabouts of the envelope containing the threaded posts is generally unknown.
It has been proposed in patent 2,129,318 to insert extra threaded posts loosely into a hollow binder. It appears that the threaded posts rattle around within the binder everytime the binder is picked up or moved. Also, the provision of a hollow binder for receiving loose threaded posts as taught by said patent is limited to one specific type of binder and requires the binder to be tilted at an angle so that the posts may be removed. To my knowledge, binders as taught by said patent have not been commercialized.